Photoluminescent metal-(Bis) ligand complexes having different ligands

Abstract

Photoluminescent complexes of copper, silver, zinc, lithium or similar metals are described, being (bis)ligand, with two different ligands. A variety of ligands may be used, the larger ligand being of a size or shape such that a pair of such ligand are prevented by steric properties from forming a (bis)ligand complex with the metal. Preferred substituents may be alkyl, aryl or alkaryl hydrocarbons, or halogen, chalcogen, nitrogen or phosphorus moieties, or included heteroatoms. Formation of the (bis)ligand complex is accomplished by maintaining the molar ratios of reactants at that which is equivalent to the (bis)ligand complex composition. The complexes are useful as optical sensors for O2, NH3 and NOx, in dye sensitization for photovoltaic devices / solar cells, in producing visible TiO2 photosensitization and in H2 production from the photochemically splitting water. These heteroleptic complexes exhibit photoluminescence equal to or better than ruthenium homoleptic complexes.

Description

1. Field of the InventionThe invention herein relates to photoluminescent metal-ligand complexes. More particularly it relates to novel complexes having extended luminescent lifetime and that are useful as optical oxygen sensors.2. Description of the Prior ArtPhotoluminescent molecules that are based on transition metals have been studied extensively for a number of years. The chemistry and photophysics of these molecules have been thoroughly investigated because of the varying potential applications for the photoluminescent transition-metal complexes. The most widely studied photoluminescent complex has been the tris(2,2'-bipyridyl) complex of ruthenium(II), written as [Ru(bpy).sub.3 ].sup.2+. The primary properties of [Ru(bpy).sub.3 ].sup.2+ that are important for most applications are a long excited-state lifetime, strong absorption in the visible region, and a high quantum yield of luminescence.Although many applications of [Ru(bpy).sub.3 ].sup.2+ have been investigated, the hig...

AI Technical Summary

Problems solved by technology

Although many applications of [Ru(bpy).sub.3 ].sup.2+ have been investigated, the high cost and low availability of ruthenium are a substantial impediment to large-scale applications of the molecule.

A wide variety of substituents are possible, subject to the limitation that no significant adverse reactions competitive to the desired complexing reaction are promoted by a particular substituent.

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